Guys,
I'm going to bring my AT8500 in to Swatch to be fixed for this problem, but I thought I could describe the problem and learn (if possible) what the causes could be. This might help me in my interaction with the Swatch staff later this week.

Essentially, the power reserve on my AT8500, purchased just over 2y ago, has dropped to about 30 hours, which is about half of what is advertised. I've tested it out before when it was new and it truly did last 60 hours. The problem has been there for 2 weeks, and some of the symptoms are:
a) stopping at 30h
b) when I'm winding it from 'flat' (when watch has run down), I seem to reach the overwind protection clicking much earlier than I expected based on prior experience
c) even on the winder, set at 900TPD, the watch still runs down, where it never used to
d) seems to wind up OK on the wrist, but once taken off, lasts ~30h, similar to when I manually wind it.
Thank goodness it's still under warranty.

Any possible diagnoses? My naive thought was that one of the 2 mainsprings had broken ... only because there are 2 barrels (implying 2 mainsprings?) but I'm probably way off. Thanks!

 

I wonder if the second barrel is damaged in some way.

 

It could be many things, so the best course of action is to simply take it in an explain the issue completely. Take photos of the watch before you bring it in also, so you have the condition documented.

And yes, 2 barrels implies 2 mainsprings, but it could have nothing to do with the barrels or springs - a watch can stop before the mainspring has wound down for many reasons, and without actually being able to see the watch, it's not really something that can be diagnosed with any certainty.

Cheers, Al

 

Quick update - I picked up the AT8500 today from Swatch. I couldn't really get very much details from the service staff, but they did say that both barrels were changed, as there was jamming due to drying up of lubrication. I confirmed on the supplied printout that both barrels were indeed changed. Pity I couldn't get a chance to talk to their watchmakers to find out.

I thought it was a bit odd that a 2 year old watch would dry up. I bought it from the Omega Boutique at the airport which has a pretty high turnover I think , though granted the 38.5mm version could've been less popular. But even if it sat there for 2 years unloved, 4 years isn't all that long ... And I thought Omega was saying that the 8500s could go longer without servicing.

Most odd. Al, any possible diagnosis based on that sketchy description? Thanks!

 

Yes in fact there is. Since you made your original post, Omega has announced (to those with access to the Extranet) that they are having problems with the DLC coated barrels in the 8500 and 9300 watches. The Swiss describe this as "a type of brown wear" which must be a translation since that doesn't make a lot of sense to me.

This "brown wear" happens where the barrel drum and cover ride on the steel barrel arbor. The solution is a new barrel design that changes how the DLC coating is applied - so old execution on the left, and the new on the right in this screen capture from their announcement:



The announcement made it clear that not all watches have this issue, so it's only showing up in a small number (so far). They are only exchanging the barrels on watches where they see this "brown wear" so not all will be upgraded as things stand now.

This could affect 8500, 8508, 8520, and 9300 models, but the new design barrel is only currently available for the 8500.

This is why when you see people on forums make claims about a new movement being "the best ever" (as some did on forums with the 8500) it has to be viewed with a grain of salt.

Time has a way of showing faults that simply can't be seen without it....

If they returned the old barrels to you, I would love to see some photos of them...

Cheers, Al

 

Al, you are amazing! Thanks for the info. Sadly, Omega did not return the barrels to me to verify the diagnosis - it would've been very interesting indeed to see what they looked like. Damn I should've thought to ask. That probably explains why they replaced both barrels.

You are absolutely right about time showing hitherto undiscovered faults. Some of these are unanticipated, and I wonder if Omega has a similar system of post-marketing surveillance that the FDA and other agencies use to track unexpected drug side effects after new drugs have been on the market.

Does Omega have a system that tracks repairs worldwide? If there's a sudden spike in the number of cases of barrel failure in 8500/9300 movements, does someone gets on the case to quickly work on a fix for the problem? It would be interesting to see how they tackle these problems - car manufacturers already have such systems in place, as shown by the number of car recalls in the past 4-5 years to fix things.

 

Well glad I could help.

I'm sure they would track faults for watches that came to their main service centers, but I can't say if it's world wide in scope or not. It may be just something done locally at each service center, and when they see enough issues of one type they run it up the ladder to Bienne. Not sure on that.

I know there is nothing in place for people like me - independents that are Omega trained and have a parts account.

I have seen a couple of "factory faults" that have happened often enough that I have asked Omega about them, and they have confirmed that they have seen them before, but there is no formal reporting structure in place.

Cheers, Al

 

Could "brown wear" be an improper translation of "brunissage", in the sense that the surface may be altered by friction? Brunissage is typically a finishing technique, but I could understand how the friction between a DLC surface and another surface could result in a similar effect that would not be desirable in such an instance.

 

Brunissage in English is burnishing, a well known technique in watchmaking, so not likely the translation you are thinking of, as the Swiss would certainly know the English term burnishing.

When done correctly burnishing does not turn the surface a different colour.

Cheers, Al

 

I was thinking about an incorrect translation..., as it would not be inconceivable that the color doesn't actually "turn brown", no matter how "$hitty" this problem is...

 

It does turn brown...

 

That's interesting and good to know. I hope my own 9300 doesn't end up being affected by this. It would be a pain. Do you have any sense of how widespread the issue might be or how old were the samples that were affected? In other words, is a watch that is affected likely to show signs early, or is this something that develops only after a long period of use (i.e., toward the end of the 4-year warranty)?

P.S. You'd be amazed at some of the stuff we see in translations emanating from Europe and Asia sometimes, even in very specialized fields; we get a good chuckle from time to time!

 

Omega did not give any numbers or further details, and only said "a small number" are affected. Keep in mind they said the same thing about the 2500 when "the stopping problem" was discovered in the PO's and other co-axials. Virtually every 2500 B or C that comes into my shop has the build up of sticky residue on it, so this problem is very common in those watches.

Right now they only have replacement barrels for 2 of the 8500 versions, so if your 9300 develops it any time soon, they may have to replace the entire movement or give you a new watch.

 

Hi Al, I was wondering (for my own learning): you mentioned 8500 versions, so how many versions of the 8500 are there? Have there been minor incremental tweaks to the 8500 calibre (like the 2500) so there's a 8500A, B etc? What tweaks were made to change the 'A' into the 'B' and how do I know whether mine is an A or B? (or maybe even 'C' ?). This is a fascinating discussion...

 

Well, the watch is closing out its second year of active service, so I guess that leaves out another two for any problems to surface and be taken care of by Omega. Given their advertised 8-year interval for servicing these new movements, and considering the significant cost of having a 9300 chrono serviced, I really hope that it can go the distance without having to replace any barrels...

 

hi HRC,

In my opening post I mentioned my watch had issues after 2y, but I miscalculated - it actually malfunctioned after only 19 months. In those 19 months I wore it frequently, and it was left on the winder when it wasn't on my wrist, so basically it only stopped completely once every 5-6 weeks or so (and even then, only for a day or two). I wonder if this also contributed to quicker development of 'brown wear'. Hope yours is fine though.

 

Wait, you're saying it's common?

Marking this: ecclesiastical.

 

I was referring more to different versions of the 8500, so 8500, 8508, 8520, etc.

Some of these have different versions, so there is an 8500A and an 8500B, and you would know which one you have by looking at the movement plate - it will say if it is a B or not.

The difference between an 8500 A and B is that the B has the silicon balance and balance spring.

Omega has charts on the technical guides showing the differences between the versions of each movement.

Cheers, Al

 

Not sure what you are referring to - the 8500 issue or the 2500?

 

Thanks Al for the info